Research Containing: Microgravity

Oxygen Lewis Number Effects on Reduced Gravity Combustion of Methanol andn-Heptane Droplets

by cfynanon 22 August 2016in Physical Sciences No comment

Reduced gravity combustion experiments were performed aboard the International Space Station with individual methanol and n-heptane droplets that had initial diameters in the 1.2-5.0 mm size range. Experiments were performed with air-inert mixtures at 0.1 and 0.07 MPa and about 298 K, where the monatomic gases helium and xenon were separately used as the added inert. These two gases have the same thermodynamic properties on a molar basis, but their transport properties are significantly different, allowing investigation of transport property effects such as Lewis number variations on combustion phenomena. The results indicate that ambient gas transport properties play an important role in determining limiting oxygen indices as well as burning rates and radiant heat output histories of flames. However, comparison with drop tower data suggests that initial droplet diameters may not play a significant role in determining limiting oxygen index values.

Effects of cooling temperature on heat pipe evaporator performance using an ideal fluid mixture in microgravity

by cfynanon 22 August 2016in Physical Sciences, Technology Development & Demonstration No comment

The effect of cooling temperature on heat pipe performance has generally received little consideration. In this paper, we studied the performance of a Constrained Vapor Bubble (CVB) heat pipe using a liquid mix- ture of 94 vol%-pentane and 6 vol%-isohexane at different cooling temperatures in the microgravity envi- ronment of the International Space Station (ISS). Using a one-dimensional (1-D) heat transfer model developed in our laboratory, the heat transfer coefficient of the evaporator section was calculated and shown to decrease with increasing cooler temperature. Interestingly, the decreasing trend was not the same across the cooler settings studied in the paper. This trend corresponded with the change in the tem- perature profile along the cuvette. When the cooling temperature went from 0 to 20 C, the temperature of the cuvette decreased monotonically from the heater end to the cooler end and the heat transfer coef- ficient decreased slowly from 456 to 401 (W m 2 K 1) (at a rate of 2.75 W m 2 K 2). However, when the cooling temperature increased from 25 to 35 C, a minimum point formed in the temperature profile, and the heat transfer coefficient dramatically decreased from 355 to 236 (W m 2 K 1) (at a rate of 11.9 W m 2 K 2). A similar change in decreasing trend was observed in the pressure gradient and liquid velocity profile. The reduced heat pipe performance at high cooling temperatures was consistent with the reduced evaporation which was indicated by the decreasing internal heat transfer and the increasing liq- uid film thickness along the cuvette as seen in the surveillance images. The result obtained is important for future heat pipe design because we now have a better understanding of the working temperature ranges of these devices.

Boiling Crisis Dynamics: Low Gravity Experiments at High Pressure

by cfynanon 22 August 2016in Physical Sciences No comment

To understand the boiling crisis mechanism, one can take advantage of the slowing down of boiling at high pressures, in the close vicinity of the liquid-vapor critical point of the given fluid. To preserve conventional bub- ble geometry, such experiments need to be carried out in low gravity. We report here two kinds of saturated boiling experiments. First we discuss the spatial experiments with SF6 at 46 ◦ C. Next we address two ground-based experi- ments under magnetic gravity compensation with H2 at 33 K. We compare both kinds of experiments and show their complementarity. The dry spots under vapor bubbles are visualized by using transparent heaters made with metal oxide films. We evidence two regimes of the dry spots growth: the regime of circular dry spots and the regime of chain coalescence of dry spots that immediately pre- cedes the heater dryout. A recent H2 experiment is shown to bridge the gap between the near-critical and low pressure boiling experiments.

Characteristics of local human skeleton responses to microgravity and drug treatment for osteoporosis in clinic

by cfynanon 22 August 2016in Biology & Biotechnology No comment

Analysis of the results of long term investigations of bones in cosmonauts on board Mir orbital sta tion(OS) and International Space Station (ISS) (n = 80) was performed. Theoretically predicted (evolution ary predefined) change in mass of different skeleton bones was found to be correlated (r = 0.904) with the position relative to Earth’s gravity vector. Vector dependence of bone loss results from local specificity of expression of bone metabolism genes, which reflects mechanical prehistory of skeleton structures in the evo lution of Homo erectus. Genetic polymorphism is accountable for high individual variability of bone loss, which is attested by the dependence of bone loss rate on polymorphism of certain genetic markers of bone metabolism. The type of the orbital vehicle did not affect the individual specific stability of the bone loss ratio in different segments of the skeleton. This fact is considered as a phenotype fingerprint of local metabolism in the form of a locus specific spatial structure of distribution of non collagen proteins responsible for posi tion regulation of endosteal metabolism. Drug treatment of osteoporosis (n = 107) evidences that recovery rate depends on bone location; the most likely reason is different effectiveness of local osteotropic interven tion into areas of bustling resorption.

The scoring quality of astronauts’ sleeps using Fuzzy C-Means (FCM) during microgravity effect in the International Space Station (ISS)

by cfynanon 22 August 2016in Biology & Biotechnology No comment

For successful health programme of Japanese astronauts during space activity in the International Space Station (ISS), we looked into the sleep quality of astronauts by using Fuzzy C-Means (FCM). At the first step, we collected observation data by following sleep schedule of astronaut Noguchi for fifteen days (26 July 2005 to 9 August 2005) during STS-114 spaceflight. The Fuzzy C-Mean (FCM) was used to design the score quality of astronauts’ sleeps. We defined three condition of sleep quality (e.g. sleepy, sleep, deep sleep) with the minimum score (zero) and maximum score (nine). Based on the preliminary result, we found that the minimum sleep score of astronaut Noguchi was from 7 to 9 August 2005 which was due to landing process and the maximum sleep score we found was later than 27 July 2005 during docking on ISS.

Isokinetic Strength Changes Following Long-Duration Space ight on the ISS

by cfynanon 22 August 2016in Biology & Biotechnology No comment

Long-duration spaceflight results in a loss of muscle strength that poses both operational and medical risks, particularly during emergency egress, upon return to Earth, and during future extraterrestrial exploration. Isokinetic testing of the knee, ankle, and trunk quantifies movement-specific strength changes following spaceflight and offers insight into the effectiveness of in-flight exercise countermeasures. We retrospectively evaluated changes in isokinetic strength for 37 ISS crewmembers (Expeditions 1–25) following 163 +/- 38 d (mean +/- SD) of spaceflight. Gender, in-flight resistance exercise hardware, and preflight strength were examined as potential modifiers of spaceflight-induced strength changes. Mean isokinetic strength declined 8–17% following space ight. One month after return to Earth, strength had improved, but small defcits of 1–9% persisted. Space flight-induced strength losses were not different between men and women. Mean strength losses were as much as 7% less in crewmembers who flew after the Advanced Resistive Exercise Device (ARED) replaced the interim Resistive Exercise Device (iRED) as the primary in-flight resistance exercise hardware, although these differences were not statistically significant. Absolute and relative preflight strength were moderately correlated (r= -0.47 and -0.54, respectively) with post flight strength changes. In-flight resistance exercise did not prevent decreased isokinetic strength after long-duration spaceflight. However, continued utilization of ARED, a more robust resistance exercise device providing higher loads than iRED, may result in greater benefits as exercise prescriptions are optimized. With reconditioning upon return to Earth, strength is largely recovered within 30 d.

THE IMPACT OF MICRO-GRAVITY ON THE RELEASE OF OAK EXTRACTIVES INTO SPIRIT

by cfynanon 22 August 2016in Physical Sciences No comment

In August 2011, an approach was made to Moët Hennessy USA by a scienti c research company called NanoRacks, LLC based in Houston,Texas, USA. NanoRacks designs and implements research programmes aboard the International Space Station via a Space Act Agreement with NASA, in conditions of micro-gravity, compared to the conditions on Earth. Given its very particular taste pro le, the Ardbeg Islay Single Malt Scotch Whisky was already well known to the scientists of NanoRacks, and they had developed an idea, involving some form of experiment, or examination, of the effect of micro-gravity on the behaviour of terpenes, the building blocks of avour for whisky spirits as well as for many other foods and wines, as research into terpenes in micro-gravity was limited.We were therefore offered an opportunity to participate in this experiment, including contributing to the design of it, however, our timescale for participation was extremely tight. We collected a quantity of Ardbeg distillate (the liquid resulting from distillation which is normally lled into oak barrels for maturation), along with oak wood shavings from the inside of a charred American White Oak ex-Bourbon barrel, which was due to be despatched from the cooperage to Ardbeg Distillery on the Island of Islay for lling with new Ardbeg distillate.These materials were carefully packaged and sent to the NanoRacks scientists in Houston, where they were packaged into their small sample testing system, known as MixStixTM, which in turn were sent to Kazakhstan to be loaded on to the Soyuz booster rocket destined for the International Space Station. A number of the MixStixTM were also sent to us to use as controls. Three days after launch, the MixStixTM were passed over to astronauts aboard the International Space Station.After an initial period of acclimatisation to the conditions aboard the ISS, in January 2012, the experiment was initiated, as the astronauts broke the glass separating walls in the individual MixStixTM, thus allowing the distillate and the oak wood shavings to come into contact with each other. At the same time on Ear th, we initiated the control experiment by breaking the separating wall in my MixStixTM on Islay (which had been sent back to me at Ardbeg Distillery from NanoRack’s laboratories in Houston, USA). The MixStixTM vials remained on the International Space Station until September 2014, nally returning to the Baikonur Cosmodrome in Kazakhstan on 12th September 2014.The vials were in conditions of micro-gravity, with the distillate and oak wood in contact, for a total of 971 days, orbiting the Earth 15 times a day during this period.The MixStixTM vials were delivered back to Ardbeg in November 2014, after which the distillate from both the micro-gravity and Earth control samples was carefully extracted.A range of comparative analyses were then carried out,to determine if there were any differences between the two sets of samples.

Optic disc edema in an astronaut after repeat long-duration space flight

by cfynanon 22 August 2016in Biology & Biotechnology No comment

BACKGROUND: A number of ophthalmic findings including optic disc edema, globe flattening, and choroidal folds have been observed in several astronauts after long-duration space flights. The authors report the first astronaut with previously documented postflight ophthalmic abnormalities who developed new pathological changes after a repeat long-duration mission. METHODS: A case study of an astronaut with 2 long-duration (6 months) exposures to microgravity. Before and after his first long-duration space flight, he underwent complete eye examination, including fundus photography. Before and after his second flight, 9 years later, he underwent fundus photography, optical coherence tomography, ocular ultrasonography, and brain magnetic resonance imaging, as well as in-flight fundus photography and ultrasound. RESULTS: After his first long-duration mission, the astronaut was documented to have eye findings limited to unilateral choroidal folds and a single cotton wool spot. During a subsequent 6-month mission, he developed more widespread choroidal folds and new onset of optic disc edema in the same eye. CONCLUSION: Microgravity-induced anatomical changes that occurred during the first mission may have set the stage for recurrent or additional changes when the astronaut was subjected to physiological stress of repeat space flight.

Capillary Channel Flow (CCF) EU2–02 on the International Space Station (ISS): An Experimental Investigation of Passive Bubble Separations in an Open Capillary Channel

by cfynanon 22 August 2016in Physical Sciences No comment

It would be signi cantly easier to design uid systems for spacecraft if the uid phases behaved similarly to those on earth. In this research an open 15:8 wedge- sectioned channel is employed to separate bubbles from a two-phase ow in a micro- gravity environment. The bubbles appear to rise in the channel and coalesce with the free surface in much the same way as would bubbles in a terrestrial environ- ment, only the combined e ects of surface tension, wetting, and conduit geometry replace the role of buoyancy. The host liquid is drawn along the channel by a pump and noncondensible gas bubbles are injected into it near the channel vertex at the channel inlet. Control parameters include bubble volume, bubble frequency, liq- uid volumetric ow rate, and channel length. The asymmetrically con ned bubbles are driven in the cross- ow direction by capillary forces until they at least become inscribed within the section or until they come in contact with the free surface, whereupon they usually coalesce and leave the ow. The merging of bubbles en- hances, but does not guarantee, the latter. The experiments are performed aboard the International Space Station as a subset of the Capillary Channel Flow experi- ments. The ight hardware is commanded remotely and continuously from ground stations during the tests and an extensive array of experiments is conducted identi- fying numerous bubble ow regimes and regime transitions depending on the ratio and magnitude of the gas and liquid volumetric ow rates. The breadth of the pub- licly available experiments is conveyed herein primarily by narrative and by regime maps, where transitions are approximated by simple expressions immediately useful for the purposes of design and deeper analysis.

Transition to chaotic thermocapillary convection in a half zone liquid bridge

by cfynanon 22 August 2016in Biology & Biotechnology, Physical Sciences

A series of fluid physics microgravity experiments with an enough long run time were performed in the ‘‘KIBO,’’ the Japanese Experiment Module aboard the International Space Station, to examine the transition to chaos of the thermocapillary convection in a half zone liquid bridge of silicone oil with a Prandtl number of 112. The temperature difference between the coaxial disks induced the thermocapillary-driven flow, and we experimentally demonstrated that the flow fields underwent a tran- sition from steady flow to oscillatory flow, and finally to chaotic flow with increasing temperature differ- ence. We obtained the surface temperature time series at the middle of the liquid bridge to quantitatively evaluate the transition process of the flow fields. By Fourier analysis, we further confirmed that the flow fields changed from a periodic, to a quasi-periodic, and finally to a chaotic state. The increasing nonlin- earity with the development of the flow fields was confirmed by time-series chaos analysis. The deter- mined Lyapunov exponent and the translation error indicated that the flow fields made transition to the chaotic field with the increasing temperature difference.

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Research Containing: Microgravity

Oxygen Lewis Number Effects on Reduced Gravity Combustion of Methanol andn-Heptane Droplets

Effects of cooling temperature on heat pipe evaporator performance using an ideal fluid mixture in microgravity

Boiling Crisis Dynamics: Low Gravity Experiments at High Pressure

Characteristics of local human skeleton responses to microgravity and drug treatment for osteoporosis in clinic

The scoring quality of astronauts’ sleeps using Fuzzy C-Means (FCM) during microgravity effect in the International Space Station (ISS)

Isokinetic Strength Changes Following Long-Duration Space ight on the ISS

THE IMPACT OF MICRO-GRAVITY ON THE RELEASE OF OAK EXTRACTIVES INTO SPIRIT

Optic disc edema in an astronaut after repeat long-duration space flight

Capillary Channel Flow (CCF) EU2–02 on the International Space Station (ISS): An Experimental Investigation of Passive Bubble Separations in an Open Capillary Channel

Transition to chaotic thermocapillary convection in a half zone liquid bridge